Lightweight’s First MoT

… well, with us, anyway.

The engine is still not perfect, but fitting a standard 12V ignition system has made it entirely usable.  I thought the slight cough when pressing the throttle down hard and the mild poppling on the over-run were a combination of only rudimentary static timing from the book figures, a lack of fine carburettor tuning and carbon deposits in the bores from all the rich running on choke.  However, the emissions test showed a product of 0.2 units (of whatever) compared to an expected 3.5, so it’s actually running clean enough to pass a test for a modern catalytic converter equipped vehicle!  It points to a lean mixture, which will help with the initial response to the loud pedal and is a simple adjustment.

Other than that, it was all good.  The lean to the left seems to be from a soft left rear spring, but nothing more serious than that.  The springs look very new, but I suspect they may be pattern parts (most likely with blue and white labels) and have quality problems.   I’ll replace both rear springs with standard new units when priorities allow.

The Lightweight did try to fail, though – halfway through the test it decided to do something I’ve never heard of before.  With the engine having already been running for the last 30 minutes or more during the test, the starter suddenly engaged.  The tester shut the ignition off very quickly but the starter just kept on going.  Oddly, the batteries were nearly drained too.  I killed it with the battery isolator switch to prevent starter heat damage.  I then disconnected the ignition switch’s feed to the solenoid and reconnected the batteries, and the starter cranked over again, showing the fault to be in the solenoid itself.  The batteries were then disconnected again.

I had to borrow the tester’s own car to go home and get my 24V charger – being a car and not commercial garage, they only have a 12V charger.  With the batteries still disconnected while charging, I removed the starter motor cable from the solenoid, leaving the ignition switch input diconnected too.  This enabled the car to be started by holding the end of the starter motor cable against the battery cable until started, then tied away safely.  The rest of the test was completed and I was able to bring it home with a curiously clean MoT – no advisories.

So, it’s determined to be a garage queen, but the Lightweight will be back on the road as soon as I fit a new solenoid.